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Proper Engine Break-in Oil and When to Switch to Synthetic Oil

I understand the benefits of Synthetic Motor Oil, but when can I start using it on my rebuilt motor? I have read or heard of mileage ranges from 500 to 10000. I would like to hear your opinion on this.

Re: Proper Engine Break-in Oil and When to Switch to Synthetic Oil

After the initial run should the oil and filters be changed and then refilled with 30w again until the 500+ mi point?

Yep...that's what I would do.

Originally Posted by rot 90na-t

What is the recommended brand, weight, and type of oil one should use to break in a fresh rebuild with forged internals?

Run any good quality API rated oil...Valvoline, Shell, and Wal-Mart Super Tech are fine. For the initial run use a Super Tech filter...I'm a believer in the "Hard & Fast" break-in method. You want to make several hard runs to ~4000 rpm...you want to get to that rpm as quickly as possible then let the car coast back down to 10 mph or so (at idle, in gear) to create a good vacuum on the engine. Then do the same thing again...3-4 times should be enough. Take the car home and change the oil/filter before running it again using the same 30W...a Super Tech filter is fine for this too. Run to the 100-200 mile point or so and change the oil again...use the same 30W or a 10W-30 dino oil and a PureOne or Wix filter. Run to the 1500 mile point and switch to a good syn oil...stick with the Wix or PureOne filters from then on.

I will no longer respond to tech questions via PM. If you have a question, put it on the forum so everyone benefits from the answer.

Originally Posted by Supracentral

However I still stand by my statement that 99 times out of 100, the weak link in the MKIII is the owner.

Re: Proper Engine Break-in Oil and When to Switch to Synthetic Oil

Originally Posted by starscream5000

Well said John . What do you think is the most crucial part? Waiting until the oil is up to operating temps before getting down on it? I've heard the first 20 miles is the most crucial part in determining that the piston rings are properly seated. Granted, it shouldn't take 20 miles to do the hard passes. Does 5-10 hard passes soud ok? With varying cruise speeds/RPM between the first 5 passes and the last set? What gear do you recommend doing this in? Do you recommend downshifting to keep the RPM's up high when decelerating from the hard pull?

Yep, the 1st 20 miles is critical...you will not be able to get the oil up to ops temp in time to make this. Just so long you have good pressure, you should be fine. You can do additional passes if you want to make "absolutely sure"...3-4 runs to ~4000 rpm through all the gears should be adequate though. You do want to downshift during the deceleration to keep the vacuum up on the motor...that's a good point After your runs and you change the oil/filter, that's when you want to keep the rpm/speed varied up through the 500 mile point...after then, you can drive normally, but I would avoid WOT runs till 1500 miles.

Originally Posted by starscream5000

But WOT from 4-4.5K RPM's, then start down shifting... What RPM would be best to put it in once you down shift? 5-5.5K? Again, 3rd gear good enough? or 4th?

Yep...take it hard up to 4000+ rpm with agressive up shifts. Then let off throttle to idle and down shift to keep rpm at 2500-3000 rpm and let it coast down mph wise through 2nd gear. Repeat as necessary

I will no longer respond to tech questions via PM. If you have a question, put it on the forum so everyone benefits from the answer.

Originally Posted by Supracentral

However I still stand by my statement that 99 times out of 100, the weak link in the MKIII is the owner.

Re: Proper Engine Break-in Oil and When to Switch to Synthetic Oil

Jdub,

what's the theory for using a constant weight oil? I'm assuming when you say 30w it is NOT multi viscosity oil? It was my understanding you want the car to be warmed up before you start the 3/4 throttle pulls to seat the rings. If so, then how could it hurt running a 5w-30 or 10w-30 for the initial startup? I'm unclear on the theory behind this, only hearing "use 30w" all over supramania.

to save me posting a second question, if you can convince me a monograde oil is the way to go, would something like the castrol HD30 do the trick?

Re: Proper Engine Break-in Oil and When to Switch to Synthetic Oil

Originally Posted by Tire Shredder

Jdub,

what's the theory for using a constant weight oil? I'm assuming when you say 30w it is NOT multi viscosity oil? It was my understanding you want the car to be warmed up before you start the 3/4 throttle pulls to seat the rings. If so, then how could it hurt running a 5w-30 or 10w-30 for the initial startup? I'm unclear on the theory behind this, only hearing "use 30w" all over supramania.

to save me posting a second question, if you can convince me a monograde oil is the way to go, would something like the castrol HD30 do the trick?

Thanks, Steve

Well, I'm not going to try and convince you of anything...I will tell you my opinion, and then you can do whatever you like

1) Straight 30W motor oil does not contain the amount of additives a multi-grade does, notability anti-wear and film thickness modifiers. This actually provides more base oil by volume in a bottle.

2) Everything I have read says to use a straight 30W on older era motors (like the 7M). It allows wear to take place to properly seat the rings. Newer (especially high performance) motors come from the factory with a syn oil fill...these engines have closer tolerances than those of the past. You have to decide what you want to go with.

3) Straight 30W is very good at dissolving assembly lube.

4) It's cheap...you're going to do a couple oil changes in the 1st 1,500 miles. Why use anything else. While your at it, grab a couple SuperTech filters at WalMart...pretty good filter, especially for as long as they will be on the car.

Castrol 30 HD is an API SM service oil...it well exceeds the oils originally spec'ed for the 7M. It will be fine.

BTW - I deleted the repeat post. This forum is moderated by me...all posts have to be approved before they will appear. I'm usually pretty quick about it, but sometimes my family, my "day job", and the dozen or so projects I have going on take precedence over me being able to answer.

I will no longer respond to tech questions via PM. If you have a question, put it on the forum so everyone benefits from the answer.

Originally Posted by Supracentral

However I still stand by my statement that 99 times out of 100, the weak link in the MKIII is the owner.